Purpose: To investigate a means to alternate image acquisition between a high‐resolution region‐of‐interest (ROI) detector and a standard flat‐panel detector(FPD) when used for neurovascular image‐guided interventions with a clinical fluoroscopic C‐arm so that the larger area detector could be used during initial parts of a procedure and the high‐resolution detector used during critical parts of the intervention when better images are needed. Method and Materials: A new detector changer was designed, fabricated, and mounted on a clinical fluoroscopic unit to allow a ROI detector such as the Micro‐Angiographic Fluoroscope (MAF) or Solid‐State X‐ray Image Intensifier (SSXII) to be introduced in front of the standard FPD to enable high‐resolution fluoroscopy,DSA, and conebeam computed tomography. The x‐ray collimation automatically adjusts the field‐of‐view (FOV) when the changer inserts or retracts the ROI detector so that the correct FOV, smaller for the ROI detector or larger for the FPD, respectively, is implemented. A touch sensor at the front of the ROI detector holder causes the entire imaging unit (FPD and ROI detector) to retract upon physical contact in order to avoid collision with a patient or other objects on or near the table. Results: The new detector changer has been installed onto a Toshiba Infinix clinical fluoroscopic C‐arm unit. The changer provides stable support for the ROI detector, allowing operator selection of high‐resolution ROI or standard FPD. The collision avoidance and automatic collimation features have worked reliably during laboratory evaluation and should provide a patient‐safe imaging capability. Conclusion: The new detector changer mounted on a commercial clinical fluoroscopic C‐arm unit provides a safe and rapid means to exchange imaging detectors to accommodate the resolution requirements of angiographic and interventional vascular imaging during the course of a procedure. (Partial support: NIH Grants R01‐EB008425, R01‐EB002873)